How in the world am I supposed to get any experience?

I'm in the process of completing a certificate program for medical billing/coding. I realize that I need to get in somewhere now to gain experience, or else I'm going to be stuck without a job. The problem is, I've sent my resume to a million local job postings for receptionist, front office clerk, unit secretary, things like that, and I'm not even getting call backs for an interview! I have two years of experience in the medical field, and I have prior experience in all the clerical stuff, so I know I'm qualified, I just wonder if it's my resume itself. I need help, because I feel like time is ticking away, and I really want to get my foot in the door awhile.